The chemotaxis and tube formation of EPCs by sE-selectin. (A) Modified Boyden chamber assay showed that sE-selectin (sE-sel) enhanced chemotaxis of EPC dose-dependently. PBS and FGF were used as negative and positive control, respectively (†P < .05; ns, P = .08; n = 4). (B) Capillary tube formation on matrigel (scale bar, 50 μm). sE-selectin induced the capillary tube formation of EPC as much as VEGF, positive control in contrast to BSA, negative control (BSA vs sE-selectin = 22.5 ± 12.6 vs 140.0 ± 35.6; †P < .05; n = 4). (C) Representative figure of EPCs, incubated on the ECM (scale bar, 50 μm). EPCs that were labeled with DiI (red) and HUVEC were cocultured. (D) Concentration of interleukin-8 (IL-8) in supernatant measured by ELISA. EPCs secreted a higher level of IL-8 when they were treated with sE-selectin (†P < .05; n = 4). (E, F) More incorporation of EPCs to ECs (E) and more capillary tube formation of EPCs (F) were observed when sE-selectin was added to culture media. Both effects were attenuated by blocking IL-8. (†P < .05; n = 4). Error bars in panels A, B, D-F represent SD.